This steel can more generally be used to replace a stainless steel of type 4301 in many applications, such as in the preceding industries or in the food and agriculture industry, including parts made from shaped wires (welded grids, etc.), profiles (strainers, etc.), axles, etc. One could also make molded parts and forged parts.
For this purpose, one is familiar with stainless steel grades of type 1.4301 and 1.4307, whose microstructure in the annealed state is essentially austenitic; in the cold-worked state, they can furthermore contain a variable proportion of work-hardened martensite. However, these steels contain large additions of nickel, whose cost is generally prohibitive. Furthermore, these grades can present problems from a technical standpoint for certain applications, since they have weak tensile characteristics in the annealed state, especially as regards the yield strength, and a not very high resistance to stress corrosion. Finally, these austenitic grades have elevated coefficients of thermal conductivity, which means that when they are used as reinforcement for concrete structures they prevent a good thermal insulation.
More recently, low-alloy austenite-ferrite grades have appeared, designated 1.4162, which contain low contents of nickel (less than 3%), no molybdenum, but high contents of nitrogen to make up for the low nickel level of these grades while preserving the desired austenite content. In order to be able to add nitrogen contents possibly greater than 0.200%, it is then necessary to add high contents of manganese. At such nitrogen levels, however, one observes the formation of longitudinal depressions in the continuous casting blooms which, in turn, cause surface defects on the rolled bars, which can be troublesome in certain cases. The manufacture of such grades is thus made particularly tricky due to this poor castability. Moreover, these grades have poor machinability.
Stainless steel grades called ferritic or ferrite-martensitic are also known whose microstructure is, for a defined range of heat treatments, composed of ferrite and martensite, such as the grade 1.4017 of standard EN10088. These grades, with chromium content generally below 20%, have elevated mechanical tensile characteristics, but do not have a satisfactory corrosion resistance.